Vacuum cleaner



G. E. LOFGREN VACUUM CLEANER Nov. 26, 1935.

Filed 001;. 6, 1932 5 Sheets-Sheet 1 M ATTORNEY G, E. LOFGREN VACUUM CLEANER Filed; Oct. 6, i932 3 Sheets-Sheet 2 :4 VENTOR A BY J/QM I115 ATTORNEY Nov. 26, 1935. G E, LOFGREN 2,022,249

VACUUM CLEANER Filed Oct. 6, 1952 s sheets-shea: s

' INVENTOR W W .fl VZ/W 4/3 ATTORNEY Patented Nov. 26, v 1935 UNITED STATES VACUUM CLEANER Gustaf Einar Lofgren, Rye, N. Y., asslgnor to Electrolux Corporation, Dover, Del., a corporation of Delaware Application October 6, 1932, Serial No. 636,499

12 Claims.

My invention relates to .vacuum cleaners and more particularly to the kind of vacuum cleaner employing a dust bag enclosed in an air-tight casing. I

The primary object of my invention is to permit the advantageous use of a larger dust bag for a given size of easing than has heretofore been possible in this kind of cleaner by providing movement in an air-tight casing of a folded dust bag to adjust the dust bag to the work and obtain higher cleaning efliciency.

Further objects and advantages will be apparent from the following description considered in connection with the accompanying drawings, which form a part of the specification, and on which:

Fig. 1 is a side View, partially in cross-section, of a vacuum cleaner unit embodying my invention in preferred form;

Fig. 2 is a transverse cross-sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a longitudinal cross-sectional view of a portion of the device shown in Fig. 1 with the dust bag fully extended;

Fig. 4 is a side view in cross-section of a vacuum cleaner unit embodying a somewhat modified form of my invention;

. Fig. 5 is a cross-sectional view taken on the line 5--5 of Fig. 4;

Fig. 6 is an end View of a cage forming part of the structure of Fig. 4;

. Fig. 7 is an end view of part of the casing of the unit shown in Fig. 4; I

Fig. 8 is a horizontal cross-sectional view of a portion of a vacuum cleaner unit embodying my invention in still another form; and

Figs. 9 and 10 show further embodiments of the invention.

The vacuum cleaner unit, as shown in Fig. 1, comprises an outer air-tight casing including a barrel portion I0, preferably cylindrical in form and made of metal or other suitablestiff, impervious material. Barrel I is open at each end. At the inlet end barrel I0 is provided with a. ring ll suitably secured thereto, while at'the outlet end a-ring I2 is secured thereto. Suitably mounted within the casing adjacent to its outlet end is anelectric motor l3, upon the shaft of which is mounted a centrifugal fan l4. Fan l4 comprises a' pair .of rotors mounted on a hub IS. The fan is surrounded by a housing l6 suitably supported in'the casing and including a front wall l8 and an intermediate wall I! between the two rotors of the fan. The walls I] and I8 are prorespectively. Aperture 20 is screened by a per.- forated plate 2| which permits the passage of air therethrough. Plate 2! carries a centrally located pin 22 to which is secured an abutment member 23. Secured to the inside of barrel ID of the casing in the plane of abutment member 23 is an annular ring 24 having a flange 25 in a vertical plane. A filter 26,'which may comprise a ring carrying one or more pieces of cloth 21, between which may be located a filter material 28, fits snugly within barrel l0 and abuts against ring- 24 and abutment 23. A perforated plate or frame 29 is disposed in front of the filter and may serve to'hold the filter in place against the abutment 23 and the ring 24.

A cylindrical cage 30 having openwork wall structure, preferably made of wire mesh and suitably reinforced to be rigid, is located within the cleaner casing between the frame 29 and the inlet end of the casing. The cage is adapted to slide in the casing and is supported therein by means of rounded projections 3| secured at points around the circumference of the cage and adapted to slide on the inside smooth wall of the casing. The cage should be made of material having sufiicient stiffness so that it will not collapse but will retain its original form. A helical spring 32 is located between the end or bottom of the cageand the frame 29 and is preferably secured to both of these members.

Within the casing and disposed within the cage is a dust separator comprising a ring 33 provided with an outwardly extending flange 34 to which is secured a suitable packing 35. A bell-shaped 35 member 36, forming one end of the cleaner casing, is clamped to barrel In by means of suitable snap fasteners, such as those illustrated at 31 in Fig. 5, and clamps the packing 35 and flange 34 between it and the ring ll. Suitably secured to ring 33 is a dust bag 38 made of flexible material adapted to retain dust but pervious to air, such as cloth. In the embodiment shown. in Figs. 1 through 3, the bag 38 has a tapered form, the larger end of the bag being secured to ring 33 while the smaller end of the bag is closed. The length of the bag 38 is greater than the length of cage 30, as is clearly shown in Fig. 3. Hence, when the bag is placed in the cage, the former becomes folded, as indicated at 39. The fact that the bag is tapered at its rear end provides space for these folds or wrinkles and it is preferable that the wrinkles be at the rear end of the bag rather than at the mouth of the .bag. Furthermore, even though the wrinkles are at the mouth of the bag when the former is first placed in cage 30, they will soon work to the rear due to the passage of air through the bag and due to the movement of cage 30, as will be later explained.

The outlet end of barrel I is closed by means of a cylindrical member 40 which is secured to ring l2 by means of snap fasteners 4 I. The member 40 is provided with a centrally located outlet 42 which is threaded. Member 36 is provided with a centrally located threaded inlet 43. A coupling 44 is adapted to be screwed into either inlet 43 or outlet 42. Coupling 44 is provided with an opening 45 which is adapted to receive a hose 45a which may be connected to a cleaning implement 45b. A pair of runners 46 are secured at their front ends to ring Ii and at their rear ends to ring I 2. The runners serve to support the vacuum cleaner and permit of easily pulling it by means of the hose over the supporting surface. The cleaner is provided with a handle 41 located above the center of gravity of the device as a whole. A switch 48 controls the operation of the motor while contact members 49 are adapted to engage an electric plug for supplying current to the motor.

It will be noted that the opening in barrel l0 adjacent to ring II has a diameter as greatasthat of any part of the casing. It is therefore possible. to withdraw cage 30 and with it the spring 32 and plate or frame 29 through the inlet end of the casing. When this has been done, filter 26 may be withdrawn and cleaned or replaced. vWhen emptying dust bag 33, it is not necessary to remove the cage, but simply to unclamp member 36 and withdrawthe'bag from the cage. I

Various parts of the cleaner are so dimensioned that when assembled, but with the fan not operating, spring 32 holds the front of cage. 30 lightly against the flange 34 of ring 33. The flange hence acts as a stop for limiting the move! ment of the cage toward the inlet end of the cleaner.

In operation, the electric motor I3 drives the fan l4, which causes a current of air to flow through the barrel ID from the inlet to the outlet. If a hose is connected to coupling 44 and to a suitable cleaning implement which is moved over a dusty surface, dust-laden air will be drawn in through opening 45 in the coupling and into bag 38. Here the dust will be deposited and the air will pass through the bag and through the openwork walls of cage 30, through filter 26 and into the fan. From the fan the air will be discharged through and around the motor 13 to the outlet 42.

The dust deposited within bag 38 has a tendency to clog the pores of the bag and to increase the resistance to flow of air through the bag. Obviously, the greater the surface of bag 38, the greater will be the amount of dust required to clog the bag and the less will be the resistance to the flow of air for a given amount of dust. By making a 'bag longer than the space in which it is to be contained and then supporting such a bag in a wire cage or the like, whereby the bag becomes folded, I am enabled to'use a dust bag having a much greater surface than would otherwise be the case. Therefore it isneccessary to clean the bag less frequently, and less power, on an average, is required to operate the fan.

, The internal diameter of the cage "should be somewhat greater than the external diameter of the bag in order that the bag willnot be pressed i against the sides of the cage, as this would tend to prevent movement of the cage within. the bar- I rel due to the fact that the front of the bag is secured to the barrel. Also, I prefer to make the bag tapered toward its closed end. This facilitates insertion of the bag into the cage and provides space for the folds or wrinkles to be formed near. the closed end of the bag where they will not interfere with the admission of dust into the bag. I

When the fan is in operation and air is flow- 1 ing through the bag, the resistance to flow of the air through the bag results in a pull on the bag. This pull is transmitted to the end of cage 30 and causes the cage to move within the casing by compressing spring 32 which opposes and limits the movement of the cage. When the motor is shut off, this pull disappears and the spring I 32 moves the cage back. toward the inlet. Likewise, whenthe cleaning implement is closed to some extent, as by'being placed relatively tightly against an article to be cleaned, less air flows into and through the bag, and hence the pul l op the bag is less. Consequently, the repeated placing of the implement on, and removing it from, the surface to be cleaned, as isdone in the normal cleaning operation, can cause the cage to move back and forth. This movement of cage 32 helps to work folds in the bag which may have formed adjacent to the inlet thereof .toward the back of the cage. It also causes the bag to fold more or less as the cage moves back and forth and thus dislodge a portion of the dirt which may have adhered to the upper part of the bag. This increases the efiectiveness and efficiency of the apparatus.

I have found that a convenient way of inserting the bag is to first start the fan and then allow the bag to be drawn into the j cage due to the suction. Unless the bag presses against the side' of thecage the bag'will be pulled into the cage 1 by the suction so that substantially all the folding is at the bottom of the cage. To avoid having the bag press against the cage, the. cleaner unitmay be stood on end with the mouth of the cage upwards while the bag is allowed to be drawn downwardly by the suction.

In Figs. 4 through 7, there is shown a somewhat modified embodiment of my invention. This differs from the form shown in- Figs. 1 through 3, chiefly in the fact that the filter 26 has been omitted. This makes it possible to insert the cage 30 from the outlet end of the barrel l0 before the motor and fan are installed. The cage, in this case, does not have to be removed in order to clean or renew the filter. Inasmuch 5 as the cage does not have to be removed through the inlet end of the casing, the ring ll may be made with an inwardlyextending flange 50 against which the flange 34 and packing 35 may bear. This in turn, reduces the outer diameter of the ring i I and results in a neater appearance for the cleaner.

In this embodiment spring 32 abuts against perforated plate 2|, a ring of insulating material The provision of a ring Slcompletely insulates the motor and fan housing from the other parts of the cleaner whereby, should a ground occur in the motor, the current will not be conducted through the casing of the vacuum cleaner. s A filter 65, which may be similar to filter 26 be located adjacent the outlet opening to deflect the air discharged from the cleaner upwardly away from the surface upon which the cleaner rests.

As shown in Fig. 6 the open end of cage 30 is provided with a ring 54 which has three outwardly extending flanges 55. A pair of abutments 56 are secured to the inside of barrel I0, preferably in conjunction with the means for securing fasteners 31 to the casing, and serve to limit the movement of cage 30 toward the inlet end of the casing by engaging flanges 55. The ring I2 is provided with three flanges 51, as is shown in Fig. 7. Flanges 5! are provided with threaded openings 58 which receive bolts 59 which secure the motor support 52 to the ring i2. Inasmuch as the cage 30 must be inserted into the barrel Hi from the outlet end thereof, it is necessary that the flanges 55 on the casing be so arranged that they will not be obstructed by the flanges 51 on ring 82 when the cage is inserted. As is apparent from Figs. 6 and '7, the respective flanges are so arranged that they do not interfere with each other.

The operation of this form of my invention is substantially the same as that described in connection with Figs. 1 through 3. The length of the bag is sufficiently greater than that of the cage so that the former will be folded when it is placed in the latter. The movement of the cage within casing ill serves to work most of the wrinkles toward the rear of the cage, as described in connection with the first embodiment.

The embodiment shown in Fig. 8 is similar to that shown in Fig. 4, with the exception that the bag 60 is of cylindrical form instead of being tapered. In this case the movement of thecage within the casing it is relied upon to work the wrinkles to the rear of the cage.

In Fig. 9, both the bag 38 and the cage 8i are tapered, the former having a greater taper than the latter. This embodiment operates in substantially the same manner as that described in Fig. l or 4, the greater space between the rear of the bag and the rear of the cage allowing for. folding of the bag at this point.

In Fig. 10, there is shown a device wherein the front end of the cage 62 is secured to thebarrel it by means of tension springs t3. Preferably, three of these springs are located equidistent from each other around the circumference of the cage. A ring St is secured within the barrel it and serves as an anchorage for one end 01 spring S3. The other ends of the springs are secured to the front of cage $2. The operation of this modification is similar to that already described and need not be, repeated.

While I have shown and described several embodiments of my invention, it is to be understood that they are for purposes of illustration only and that my invention is not to be limited except by the appended claims viewed in the light of the prior art.

What I claim is:

i. In a vacuum cleaner, a casing having an inlet for dust-laden air and an outlet for air from which dust has been removed, means to cause flow of air through said casing, a dust separator of flexible air-pervious material in said casing so positioned therein that the air which enters as dust-laden air passes therethrough, said dust separator being mounted in the casing so as to be distensible due to the flow of air, and movable means to retain said separator in partially distended condition, the last mentioned means being movable by increased distention of said separator in variable degree depending on the pressure drop through the dust separator. 5

2. In a vacuum cleaner, a casing having an inlet for dust-laden air and an outlet for air from which dust has been removed, means to cause flow 'of air through sald'casing, a dust bag of flexible air-pervious material in said casing 10 having one end thereof fixed against movement and so positioned within the casing that all the air which enters as dust-laden air passes therethrough, said dust bag being distensible due to the flow of air, a movable member in said casing against which the dust bag is pressed due to pressure drop therethrough and which resists distention of the dust bag, and resilient means for yieldably pressing said member against the dust bag, whereby on increase in pressure drop said member is moved in one direction and on decrease in pressure drop the resilient means moves said member in the opposite direction.

3. In a vacuum cleaner, an air-tight casing provided with a dust-laden air inlet opening and an air outlet opening, means for causing flow of air therethrough, an openwork wall structure movably mounted in said casing,'resilient means for opposing movement of said structure, and a dust bag of air-pervious flexible'material disposed in said, casing so that dust-laden air flows thereinto, said bag being of such size and so held in the casing as to press against and cause move--' ment of said structure due to the flow of air therethrough.

l. In a vacuum cleaner, an air-tight casing provided with a dust-laden air inlet opening and an air outlet opening, means for causing flow of air therethrough, anopenwork' wall structure movably mounted in said casing and providing with 40 said casing a space for reception of a dust bag, resilient means for opposing movement of said structure, and a dust bag of air-pervious flexible material in said space, the length of said bag being greater than the length of said space,

ber in said casing, means for drivingsaid fan,

an openwork Wall structure movably mounted in said casing between said fan and said inlet, resilient means for opposing movement of said structure comprising a spring between said structureand said fixed member, and a dust bag of air-pervious flexible material in said casing having one end fixed. to the casing, said has being so large as to bear against said structure without being fully distended and so positioned as to receive all the dust-laden air passing through said inlet opening.

6. in a vacuum cleaner, an elongated casing, means for mounting said casing horizontally above. a horizontal surface, a cage slidably mounted in said casing and substantially as wide as the inside of said casing, means for causing flow of air through said casing, a dust-bag disposed in said cage and narrower than said cage, said dust bag being positioned to receive all the dust-laden air passing through said inlet and a .as the inside of said casing'and providing a space ,for a dust-bag, means for causing flow of air through said casing, resilient means opposing sliding movement of said cage, and a dust-bag .disposed in said cage and narrower than said cage'and longer than the length of said space, said cage serving to hold said dust-bag away from the casing and said dust bag having one end -secured to the casing and positioned to receive all the dust-laden air entering through the inlet.

8. In a vacuum cleaner, a casing provided with ,an inlet opening and an outlet opening, means for causing flow of air therethrough, movable means to retain a dust bag therein in partially ,distended condition, and resilient means for gov- .erning movement of said retaining means due to variations in air pressure diflferential between opposite sides of the dust bag.

9.In a vacuum cleaner, a casing provided ,with a dust-laden air inlet opening and an air ,outlet opening, means for causing flow of air therethrough, a dust separator in said casing position to receive dust-laden air passing through said inlet, movable means to retain the dust separator therein in partially distended con.-

.dition, a part of the dust separator being movable with respect to the remainder, and means responsive to variations in pressure drop through the dust separator to govern movement of the .movable means so that the movable part of the dust separator moves progressively farther in -cne .direction as dust accumulates therein.

10. In a vacuum cleaner, a casing provided with an inlet opening and an outlet opening, means for causing'flow of air therethrough, a suction tool, a hose adapted to connect the suction tool with the casing, a dust separator in said casing positioned to receive dust-laden air passing throughvsaid inlet, movable means to re- .tain thedust separator therein in partially distended condition, a part of the dust separator being movable with respect to the remainder, and means responsive to variations in application of the suction tool to an object to be cleaned to govern movement of the movable means.

11. In a vacuum cleaner, structure forming a dust bag chamber having a movable wall part, a dust bag mounted in said chamber, means to cause flow of air through said dust bag, part of said dust bag being fixed against movement and said dust bag being distensible to a size too large for accommodation in said chamber whereby on e'ng distended in said chamber the dust bag presses against said movable wall part, and means whereby, said wall part is movable in variable degree depending on variation in pressure drop through the dust bag.

12. In a vacuum cleaner, structure forming a dust bag chamber having a movable wall part, a dust bag mounted in said chamber, means to cause flow of air through said dust bag, part of said dust bag being fixed against movement and said dust bag being distensible to a size too large for accommodation in said chamber whereby on being distended in said chamber the dust bag presses against said movable wall part and said movable wall part resists d'stention of the dust bag, and resilient means for yieldably pressing said movable wall part against the .dust bag, whereby on increase in pressure drop through the dust bag said movable wall part is moved in one direction and on decrease in pressure drop the resilient means moves said wall part in the opposite direction. 1 1

GUSTAF EINAR LOFGREN. 

